Glass rovings impregnated with thermoplastic polyurethane resins



United States Patent 3,538,700 GLASS ROVINGS IMPREGNATED WITH THERMO-PLASTIC POLYURETHANE RESINS Peter H. Hofer, Berkeley Heights, N.J.,assignor to Union Carbide Corporation, a corporation of New York NoDrawing. Continuation-impart of applications Ser. No. 502,364, Oct. 22,1965, and Ser. No. 693,460, Dec. 26, 1967. This application July 16,1968, Ser. No. 745,131

Int. Cl. D02g 3/18; C03c 25/02 U.S. Cl. 57-139 8 Claims ABSTRACT OF THEDISCLOSURE This invention relates to glass rovings, impregnated withthermoplastic polyurethane resins, which are char acterized by a lowweight-high tensile strength ratio, by relatively low elongation, byexcellent flexibility characteristics and by excellent abrasionresistance and are excellently suited for use in nonwoven, nonbraidedrope, in aerial antenna systems and also a buoyant submarine cables suchas submarine antenna systems capable of transmitting and receiving radiosignals while the submarine is submerged at greater than periscopedepth.

This application is a continuation-in-part application of my copendingapplication Ser. No. 502,364, filed Oct. 22, 1965, and also of mycopending application Ser. No. 693,460, filed Dec. 26, 1967.

This invention relates to glass rovings which are impregnated withthermoplastic polyurethane resins. More particularly, this inventionrelates to glass rovings, im-

' pregnated with thermoplastic polyurethane resins, which arecharacterized by a low weight-high tensile strength ratio, by relativelylow elongation, by relatively high flexibility characteristics and byrelatively high abrasion resistance (filament to filament abrasion) andare excellently suited for use in nonwoven, nonbraided rope, in aerialantenna systems and also in submarine antenna systems which are capableof transmitting and receiving radio signals while the submarine issubmerged at greater than periscope depth.

One type of submarine antenna system which has been commonly used totransmit and to receive radio signals, while the submarine is submergedat greater than periscope depth, is made up of an electrical conductor,such as a copper conductor and as successive layers surrounding thiselectric conductor (1) insulation, as for example, thermoplasticinsulation such as polyethylene (2) metal braid, such as copper braidwhich serves as the second conductor (3) a second layer of thermoplasticinsulation (4) metal filaments, such as steel filaments, which serve toprovide strength for the system and (5) a foamed jacket such aspolyethylene foam which serves to provide buoyancy to the system.

Although this type of antenna system has been used for receiving and fortransmitting radio signals from submerged submarines, its performancehas been relatively poor. The poor performance of such a system is due,primarily, to the fact that it is not sufiiciently bouyant to float ontop of the water, which is necessary in order that it properly transmitand receive.

In an attempt to improve the buoyancy of such systems, it has beenproposed to reduce the weight thereof by eliminating metalfilamentstherefrom. This expediency has not proved to be particularly successful.It has been found that in order to increase the buoyancy of such systemsto a significant degree, it is necessary to drastically reduce thenumber of metal filaments therein. This results in an antenna systemwhich is too weak, structurally, to have any great value. That is tosay, such antenna systems do not have sufiicient tensile strength toWithstand,

without breaking, forces, due to drag to which the antenna system issubjected when it is in use and the submarine is moving at relativelyhigh speeds.

The present invention provides glass rovings impregnated withthermoplastic polyurethane resins which are characterized by a lowweight-high tensile strength ratio, the tensile strengths being as highas 500,000 p.s.i., by relatively low elongation, generally on the orderof less than about 3 percent, by excellent flexibility characteristicsand by excellent abrasion resistance. Buoyant cable systems, such asbuoyant antenna systems, in Which the impregnated glass rovings of thisinvention are used, have 8 times the tensile strength of a system whichhas the same buoyancy characteristics but has steel filaments in lieu ofthe impregnated glass rovings.

The impregnated glass rovings of this invention contain from about 8 toabout 40 percent by weight and preferably about 18 to about 22 percentby weight thermoplastic polyurethane resin based on the combined weightof the glass and polyurethane resin.

The glass rovings themselves are made up of a plurality of individualglass filaments generally ranging in number from about 50 to about20,000, with the'filaments ranging, generally, in diameter of from about5 microns to about 25 microns. For purposes of this invention the glassroving described below is particularly preferred:

Diameter of glass filaments=about 8 to about 10 microns Number offilaments per end=about 200-210 Number of ends per roving=about 6 toabout 40 The thermoplastic polyurethane resins which are used toimpregnate the glass rovings are well known materials and are generallyprepared by reacting a diisocyanate with a dihydric compound to producea polymer having more than one group per molecule. As a general rule,the diisocyanate and dihydric compound are admixed in about equivalentamounts and reacted to a thermoplastic product.

Both aliphatic and aromatic diisocyanates can be used as reactants withdihydric compounds to produce thermoplastic polyurethane resins.Illustrative of such diisocyanates are the following:tetramethylene-l,4-diisocyanate, hexamethylene-1,6-diisocyanate,p-phenylene diisocyanate, m-phenylene diisocyanate 1-chlorophenylene-2,4-diisocyanate, naphthalene 1,5 diisocyanate, tolylene- 2,4diisocyanate, diphenylmethane-4,4-diisocyanate, diphenyl4,4-diisocyanate, cyclohexylene-l,4-diisocyanate,cyclohexylene-l,2-diisocyanate and the like.

Of the dihydric compounds which are used to react with thediisocyanates, the polyalkylene glycols are preferred.

Suitable polyalkylene glycols can be represented by the formula:

HOtROi H wherein R is an alkylene radical such as methylene, propyleneand the like and n is an integer greater than 2. Also suitable are thecommercially available glycols marketed under the name Carbowax.Particularly preferred are the poly(ethylene glycols) and thepoly(propylene glycols) having an average molecular weight of about 300to 750. Other suitable dihydric compounds are the hydroxyl terminatedpolyesters as for example a hydroxyl terminated polyester of adipic acidand l,4-butanediol.

The impregnation of the glass rovings with the thermoplasticpolyurethane resins can be carried out by forming a solution ofthepolyurethane resin in a suitable solvent such as dimethyl formamide,tetrahydrofuran, a ketone etc. and then submerging a fully Wound spoolof glass roving in the solution, subjecting the solution and thesubmerged spool to a reduced pressure of about 0.5 mm. to about 15 mm.of Hg and maintaining this pressure until cessation of bubbling and thenincreasing the pressure to about 1,000 to about 6,000 lbs. per squareinch for about two to about ten minutes and thereafter allowing thesystem to return to atmospheric pressure.

Alternatively, the glass roving can be impregnated by passing the rovingthrough a solution of the thermoplastic polyurethane resin and thenpassing the coated roving through a rolling bank of the polyurethanesolution as described in my copending application Ser. No. 693,460,filed Dec. 26, 1967.

In formulating the coating solutions, it is customary to provide thesolutions with a solids content of about 15 percent by weight to about40 percent by weight.

If desired, colorants, stabilizers, ultra-violet light absorbers and thelike can be added to the polyurethane resins, in amounts well known inthe art, prior to impregnation of the glass rovings.

The glass rovings of Examples 1-2, were impregnated by the proceduredescribed in Example 1 of my copending application Ser. No. 502,364,filed Oct. 22, 1965.

The glass rovings of Examples 3-5 were impregnated by the proceduredescribed in Example 1 of my copending application Ser. No. 693,460,filed Dec. 2 6, 1967.

Tests noted in the examples of this application were carried outaccording to procedures described in Appendix A page 88 and seq. of areport entitled U.S. Navy Underwater Sound Laboratory ContractN-140-66C- 0403," dated Feb. 15, 1968, with the breaking strength, inpounds, being the load break, of the tensile strength test.

EXAMPLE 1 Impregnated glass roving:

88 percent by weight glass (glass roving had 20 ends and 204 filamentsper end with each filament being about 12 microns in diameter).

12 percent by weight of a thermoplastic polyurethane resin (reactionproduct of polybutylene adipatemethylene phenylene diisocyanate andbutanediol).

Coating solution:

15 percent by weight thermoplastic polyurethane resin. Solventdimethylformamide. Properties of the impregnated glass roving:

Breaking strength=94 lbs. Tensile strength (glass area)=195,000 p.s.i.Elongation=2.6 percent.

EXAMPLE 2 Impregnated glass roving:

'88 percent by weight glass (described in Example 1). 12 percent byweight of a thermoplastic polyurethane resin (reaction product oftolylene-1,4-diisocyanate and ethylene glycol).

Coating solution:

40 percent by weight thermoplastic polyurethane resin.Solvent-methylethyl ketone.

Properties of the impregnated glass roving:

Breaking strength=166 lbs. Tensile strength (glass area) =206,000 p.s.i.Elongation=2.6 percent.

EXAMPLE 3 Impregnated glass roving:

91.8 percent by weight glass (described in Example 1). 8.2 percent byweight thermoplastic polyurethane resin (reaction product ofdiphenylmethane-1,4-diisocyanate and a hydroxyl terminated polyester of4 1,4-butanediol and adipic acid containing about 40 percent by weightcombined diisocyanate).

Coating solution:

15 percent by weight thermoplastic polyurethane resin. Solvent5050mixture by weight of acetone and tetrahydrofuran.

Properties of the impregnated glass roving:

Breaking strength=93 lbs. Tensile strength (glass area)=190,000 p.s.i.Elongation=2.4 percent.

Impregnated glass roving:

84.8 percent by weight glass (described in Example 1). 15.2 percent byweight thermoplastic polyurethane resin (described in Example 3).

Coating solution:

25 percent by weight thermoplastic polyurethane resin.Solvent-tetrahydrofuran.

Properties of the impregnated glass roving:

Breaking strength= lbs. Tensile strength (glass area)=2l0,000 p.s.i.Elongation=2.5 percent. Abrasion resistance=526 strokes.

EXAMPLE 5 This impregnated glass roving was aged for 16 months underambient conditions. At the end of this period of time, there was nosignificant change in tensile strength. Also, the impregnated glassroving was immersed in water for seven days. At the end of this time,there was no significant change in tensile strength.

In order to further demonstrate the unique properties of the glassrovings of this invention, Example 5 was repeated using the polyurethaneresin of Example 5 as well as other thermoplastics. The polymer contentand properties of the impregnated rovings are noted below:

Tensile strength Abrasion Percent by weight in p.s.i. resistancethermoplastic glass area in strokes Example 6.... 13.6 polyurethane-439, 000 66 Example 7-.-. 16. 1 p0lyuretl1ane.. 432, 000 83 Example8-.-. 18. 6 polyurethane.. Example 9.--- 24. 0 polyurethane Example10... 29. 2 polyurethane Control 1.. 14.0 copolymer of ethylenevmylacetate containing about 14 ercent by weight combine vinylacetate.

The impregnated glass rovings of Examples 1-10 were formed intononwoven, nonbraided rope by methods well known in the art, as forexample, are described in US. Pat. No. 3,371,476 and also by helicallywinding impregnated glass rovings together. Cables were also formed fromthe impregnated glass rovings of this invention, by methods Well knownin the art.

It is to be understood that the disclosure of my copending applications,previously identified in this application are incorporated herein byreference.

What is claimed is: r

1. A glass roving impregnated with a thermoplastic nonfoamedpolyurethane resin formed by the reaction of approximately equivalentamounts of a diisocyanate and dihydric compound wherein the polyurethaneresin content is about 8 to about 40 percent by weight based on thecombined weight of glass and polyurethane resin.

2. A glass roving as defined in claim 1 wherein the polyurethane resincontent is about 18 to about 22 percent by weight based on the combinedweight of glass and polyurethane resin.

3. A glass roving as defined in claim 1 wherein each glass roving ismade up of glass filaments of about 50 to about 20,000 in number withthe diameter of each filament being about 5 microns to about 25 microns.

4. A glass roving as defined in claim 3 wherein the glass filaments havea diameter of about 8 to about 10 microns, the number of filaments perend is about 200 to about 210 and the number of ends per roving is about6 to about 40.

5. A glass roving as defined in claim 1 wherein the polyurethane resinis the reaction product of diphenylmethane 1,4-dissocyanate and ahydroxyl terminated polyester of 1,4-butanediol and adipic acid.

6. A glass roving as defined in claim 1 wherein the polyurethane resinis the reaction product of tolylene-l,4- diisocyanate and ethyleneglycol.

7. A glass roving as defined in claim 1 wherein the thermoplasticpolyurethane resin is the reaction product of polybutylene adipate,methylene phenylene diisocyanate and butanediol.

8. A nonwoven, nonbraided rope comprising glass rovings impregnated witha polyurethane resin as defined in claim 1.

References Cited UNITED STATES PATENTS 2,862,281 12/1958 Klauser 117-161X 2,993,813 7/1961 Tischbein 117161 X 3,091,019 5/1963 Wetterau 161'93 X3,245,827 4/1966 Weber 117-126 X 3,271,825 9/1966 Dennis 2875 X3,323,975 6/1967 Marzocchi et al. 117126 X 3,371,476 3/1968 Costello eta1 2875 X WILLIAM D. MARTIN, Primary Examiner D. COHEN, AssistantExaminer US. Cl. X.R.

